The present invention is directed to novel imidazopyrazines, their salts, and compositions comprising them. In particular, the present invention is directed to imidazopyrazines as novel tyrosine kinase inhibitors that inhibit tyrosine kinase enzymes in animals, including humans, for the treatment and/or prevention of various diseases and conditions such as cancer.
Phosphoryl transferases are a large family of enzymes that transfer phosphorous-containing groups from one substrate to another. Kinases are a class of enzymes that function in the catalysis of phosphoryl transfer. The phosphorylation is usually a transfer reaction of a phosphate group from ATP to the protein substrate. Almost all kinases contain a similar 250-300 amino acid catalytic domain. Protein kinases, with at least 400 identified, constitute the largest subfamily of structurally related phosphoryl transferases and are responsible for the control of a wide variety of signal transduction processes within the cell. The protein kinases may be categorized into families by the substrates they phosphorylate (e.g., protein-tyrosine, protein-serine/threonine, etc.). Protein kinase sequence motifs have been identified that generally correspond to each of these kinase families. Lipid kinases (e.g. PI3K) constitute a separate group of kinases with structural similarity to protein kinases.
The “kinase domain” appears in a number of polypeptides which serve a variety of functions. Such polypeptides include, for example, transmembrane receptors, intracellular receptor associated polypeptides, cytoplasmic located polypeptides, nuclear located polypeptides and subcellular located polypeptides. The activity of protein kinases can be regulated by a variety of mechanisms and any individual protein might be regulated by more than one mechanism. Such mechanisms include, for example, autophosphorylation, transphosphorylation by other kinases, protein-protein interactions, protein-lipid interactions, protein-polynucleotide interactions, ligand binding, and post-translational modification.
Phosphorylation of target proteins occurs in response to a variety of extracellular signals (hormones, neurotransmitters, growth and differentiation factors, etc.), cell cycle events, environmental or nutritional stresses, etc. Protein and lipid kinases regulate many different cell processes by adding phosphate groups to targets such as proteins or lipids. Such cell processes include, for example, proliferation, growth, differentiation, metabolism, cell cycle events, apoptosis, motility, transcription, translation and other signaling processes. Kinase catalyzed phosphorylation acts as molecular on/off switches to modulate or regulate the biological function of the target protein. Thus, protein and lipid kinases can function in signaling pathways to activate or inactivate, or modulate the activity (either directly or indirectly) of the targets. These targets may include, for example, metabolic enzymes, regulatory proteins, receptors, cytoskeletal proteins, ion channels or pumps, or transcription factors.
A partial list of protein kinases includes abl, AKT, bcr-abl, Blk, Brk, Btk, c-kit, c-met, c-src, CDK1, CDK2, CDK3, CDK4, CDKS, CDK6, CDK7, CDK8, CDK9, CDK10, cRaf1, CSFir, CSK, EGFR, ErbB2, ErbB3, ErbB4, Erk, Fak, fes, FGFR1, FGFR2, FGFR3, FGFR4, FGFR5, Fgr, flt-1, Fps, Frk, Fyn, Hck, IGF-1R, INS-R, Jak, KDR, Lck, Lyn, MEK, p38, PDGFR, PIK, PKC, PYK2, ron, tie, tie2, TRK, Yes, and Zap70. Thus, protein kinases represent a large family of proteins which play a central role in the regulation of a wide variety of cellular processes, maintaining control over cellular function. Uncontrolled signaling due to defective control of protein phosphorylation has been implicated in a number of diseases and disease conditions, including, for example, inflammation, cancer, allergy/asthma, disease and conditions of the immune system, disease and conditions of the central nervous system (CNS), cardiovascular disease, dermatology, and angiogenesis.
Initial interest in protein kinases as pharmacological targets was stimulated by findings that many viral oncogenes encode structurally modified cellular protein kinases with constitutive enzyme activity. One early example was the Rous sarcoma virus (RSV) or avian sarcoma virus (ASV), which caused highly malignant tumors of the same type or sarcomas within infected chickens. Subsequently, deregulated protein kinase activity, resulting from a variety of mechanisms, has been implicated in the pathophysiology of a number of important human disorders including, for example, cancer, CNS conditions, and immunologically related diseases. The development of selective protein kinase inhibitors that can block the disease pathologies and/or symptoms resulting from aberrant protein kinase activity has therefore become an important therapeutic target.
Protein tyrosine kinases (PTKs) are enzymes that catalyse the phosphorylation of specific tyrosine residues in cellular proteins. Such post-translational modification of the substrate proteins, often enzymes themselves, acts as a molecular switch regulating cell proliferation, activation or differentiation (for review, see Schlessinger and Ullrich, 1992, Neuron 9:383-391). Aberrant or excessive PTK activity has been observed in many disease states including benign and malignant proliferative disorders as well as diseases resulting from inappropriate activation of the immune system (e.g., autoimmune disorders), allograft rejection, and graft vs. host disease. In addition, endothelial-cell specific receptor PTKs such as KDR and Tie-2 mediate the angiogenic process, and are thus involved in supporting the progression of cancers and other diseases involving inappropriate vascularization (e.g., diabetic retinopathy, choroidal neovascularization due to age-related macular degeneration, psoriasis, arthritis, retinopathy of prematurity, infantile hemangiomas).
Tyrosine kinases can be of the receptor-type (having extracellular, transmembrane and intracellular domains) or the non-receptor type (being wholly intracellular). The Receptor Tyrosine Kinases (RTKs) comprise a large family of transmembrane receptors with at least nineteen distinct RTK subfamilies having diverse biological activities. The RTK family includes receptors that are crucial for the growth and differentiation of a variety of cell types (Yarden and Ullrich, Ann. Rev. Biochem. 57:433-478, 1988; Ullrich and Schlessinger, Cell 61:243-254, 1990). The intrinsic function of RTKs is activated upon ligand binding, which results in phosphorylation of the receptor and multiple cellular substrates, and subsequently in a variety of cellular responses (Ullrich & Schlessinger, 1990, Cell 61:203-212). Thus, RTK mediated signal transduction is initiated by extracellular interaction with a specific growth factor (ligand), typically followed by receptor dimerization, stimulation of the intrinsic protein tyrosine kinase activity and receptor transphosphorylation. Binding sites are thereby created for intracellular signal transduction molecules and lead to the formation of complexes with a spectrum of cytoplasmic signaling molecules that facilitate the appropriate cellular response such as cell division, differentiation, metabolic effects, and changes in the extracellular microenvironment (see Schlessinger and Ullrich, 1992, Neuron 9:1-20).
Proteins with SH2 (src homology-2) or phosphotyrosine binding (PTB) domains bind activated tyrosine kinase receptors and their substrates with high affinity to propagate signals into cell. Both of the domains recognize phosphotyrosine. (Fantl et al., 1992, Cell 69:413-423; Songyang et al., 1994, Mol. Cell. Biol. 14:2777-2785; Songyang et al., 1993, Cell 72:767-778; and Koch et al., 1991, Science 252:668-678; Shoelson, Curr Opin. Chem. Biol. (1997), 1(2), 227-234; Cowburn, Curr Opin. Struct. Biol. (1997), 7(6), 835-838). Several intracellular substrate proteins that associate with RTKs have been identified. They may be divided into two principal groups: (1) substrates which have a catalytic domain; and (2) substrates which lack such a domain but serve as adapters and associate with catalytically active molecules (Songyang et al., 1993, Cell 72:767-778). The specificity of the interactions between receptors or proteins and SH2 or PTB domains of their substrates is determined by the amino acid residues immediately surrounding the phosphorylated tyrosine residue. For example, differences in the binding affinities between SID domains and the amino acid sequences surrounding the phosphotyrosine residues on particular receptors correlate with the observed differences in their substrate phosphorylation profiles (Songyang et al., 1993, Cell 72:767-778). Observations suggest that the function of each receptor tyrosine kinase is determined not only by its pattern of expression and ligand availability but also by the array of downstream signal transduction pathways that are activated by a particular receptor as well as the timing and duration of those stimuli. Thus, phosphorylation provides an important regulatory step which determines the selectivity of signaling pathways recruited by specific growth factor receptors, as well as differentiation factor receptors.
Several receptor tyrosine kinases such as FGFR-1, PDGFR, Tie-2 and c-Met, and growth factors that bind thereto, have been suggested to play a role in angiogenesis, although some may promote angiogenesis indirectly (Mustonen and Alitalo, J. Cell Biol. 129:895-898, 1995). One such receptor tyrosine kinase, known as “fetal liver kinase 1” (FLK-1), is a member of the type III subclass of RTKs. Human FLK-1 is also known as “kinase insert domain-containing receptor” (KDR) (Terean et al., Oncogene 6:1677-83, 1991). It is also called “vascular endothelial cell growth factor receptor 2” (VEGFR-2) since it binds vascular endothelial cell growth factor (VEGF) with high affinity. The murine version of FLK-1/VEGFR-2 has also been called NYK. (Oelrichs et al, Oncogene 8(1):11-15, 1993). Numerous studies (such as those reported in Millauer et al., supra), suggest that VEGF and FLK-1/KDR/VEGFR-2 are a ligand-receptor pair that play an important role in the proliferation of vascular endothelial cells (vasculogenesis), and the formation and sprouting of blood vessels (angiogenesis). Accordingly, VEGF plays a role in the stimulation of both normal and pathological angiogenesis (Jakeman et al., Endocrinology 133:848-859, 1993; Kolch et al., Breast Cancer Research and Treatment 36: 139-155, 1995; Ferrara et al., Endocrine Reviews 18(1); 4-25, 1997; Ferrara et al., Regulation of Angiogenesis (ed. L D. Goldberg and E. M. Rosen), 209-232, 1997). In addition, VEGF has been implicated in the control and enhancement of vascular permeability (Connolly, et al., 1. BioI. Chem. 264: 20017-20024, 1989; Brown et al., Regulation of Angiogenesis (ed. L D. Goldberg and E. M. Rosen), 233-269, 1997).
Another type III subclass RTK related to FLK-1/KDR (DeVries et al. Science 255:989-991, 1992; Shibuya et al., Oncogene 5:519-524, 1990) is “fms-like tyrosine kinase-I” (Flt-1), also called “vascular endothelial cell growth factor receptor 1” (VEGFR-1). Members of the FLK-1/KDR/VEGFR-2 and Flt-1/VEGPR-1 subfamilies are expressed primarily on endothelial cells. These subclass members are specifically stimulated by members of the VEGF family of ligands (Klagsbum and D'Amore, Cytokine & Growth Factor Reviews 7: 259270, 1996). VEGF binds to Flt-1 with higher affinity than to FLK-1/KDR and is mitogenic toward vascular endothelial cells (Terman et al., 1992, supra; Mustonen et al. supra; DeVries et al., supra). Flt-1 is believed to be essential for endothelial organization during vascular development. Flt-1 expression is associated with early vascular development in mouse embryos, and with neovascularization during wound healing (Mustonen and Alitalo, supra). Expression of Flt-1 in monocytes, osteoclasts, and osteoblasts, as well as in adult tissues such as kidney glomeruli suggests an additional function for this receptor that is no related to cell growth (Mustonen and Alitalo, supra).
Placenta growth factor (PlGF) has an amino acid sequence that exhibits significant homology to the VEGF sequence (Park et al., 1. Biol. Chem. 269:25646-54, 1994; Maglione et al. Oncogene 8:925-31, 1993). As with VEGF, different species of PlGF arise from alternative splicing of mRNA, and the protein exists in dimeric form (Park et al., supra). PlGF-1 and PlGF-2 bind to Flt-1 with high affinity, and PlGF-2 also avidly binds to neuropilin-1 (Migdal et al., 1. Biol. Chem. 273 (35): 22272-22278), but neither binds to FLK-1/KDR (Park et al., supra). PlGF has been reported to potentiate both the vascular permeability and mitogenic effect of VEGF on endothelial cells when VEGF is present at low concentrations (purportedly due to heterodimer formation) (Park et al., supra).
VEGF-B is thought to play a role in the regulation of extracellular matrix degradation, cell adhesion, and migration through modulation of the expression and activity of urokinase type plasminogen activator and plasminogen activator inhibitor 1 (Pepper et al., Proc. Natl. Acad. Sci. U.S.A. (1998), 95(20):11709-11714).
VEGF-C can also bind KDR/VEGFR-2 and stimulate proliferation and migration of endothelial cells in vitro and angiogenesis in in vivo models (Lymboussaki et. al., Am. J Pathol. (1998), 153(2):395-403; Witzenbichler et al., Am. J. Pathol. (1998), 153(2), 381-394). The transgenic overexpression of VEGF-C causes proliferation and enlargement of only lymphatic vessels, while blood vessels are unaffected. Unlike VEGF, the expression of VEGF-C is not induced by hypoxia (Ristimaki et al, J. Biol. Chem. (1998), 273(14), 8413-8418).
Structurally similar to VEGF-C, VEGF-D is reported to bind and activate at least two VEGFRs, VEGFR-3/Flt-4 and KDR/VEGFR-2. It was originally cloned as a c-fos inducible mitogen for fibroblasts and is most prominently expressed in the mesenchymal cells of the lung and skin (Achen et al, Proc. Natl. Acad. Sci. U.S.A. (1998), 95(2), 548-553 and references therein). VEGF, VEGF-C and VEGF-D have been claimed to induce increases in vascular permeability in vivo in a Miles assay when injected into cutaneous tissue (PCT/US97/14696; WO98/07832, Witzenbichler et al., supra). The physiological role and significance of these ligands in modulating vascular hyperpermeability and endothelial responses in tissues where they are expressed remains uncertain.
Tie-2 (TEK) is a member of a recently discovered family of endothelial cell specific RTKs involved in critical angiogenic processes such as vessel branching, sprouting, remodeling, maturation and stability. Tie-2 is the first mammalian RTK for which both agonist ligands (e.g., Angiopoietin1 (“Ang1”), which stimulates receptor autophosphorylation and signal transduction), and antagonist ligands (e.g., Angiopoietin2 (“Ang2”)), have been identified. The current model suggests that stimulation of Tie-2 kinase by the Ang1 ligand is directly involved in the branching, sprouting and outgrowth of new vessels, and recruitment and interaction of periendothelial support cells important in maintaining vessel integrity and inducing quiescence. The absence of Ang1 stimulation of Tie-2 or the inhibition of Tie-2 autophosphorylation by Ang2, which is produced at high levels at sites of vascular regression, may cause a loss in vascular structure and matrix contacts resulting in endothelial cell death, especially in the absence of growth/survival stimuli. Recently, significant upregulation of Tie-2 expression has been found within the vascular synovial pannus of arthritic joints of humans, consistent with a role in the inappropriate neovascularization, suggesting that Tie-2 plays a role in the progression of rheumatoid arthritis. Point mutations producing constitutively activated forms of Tie-2 have been identified in association with human venous malformation disorders. Tie-2 inhibitors are, thereful, useful in treating such disorders, and in other situations of inappropriate neovascularization.
Non-receptor tyrosine kinases represent a collection of cellular enzymes which lack extracellular and transmembrane sequences (see, Bohlen, 1993, Oncogene 8:2025-2031). Over twenty-four individual non-receptor tyrosine kinases, comprising eleven (11) subfamilies (Src, Frk, Btk, Csk, Abl, Zap70, Fes/Fps, Fak, Jak, Ack and LIMK) have been identified. The Src subfamily of non-receptor tyrosine kinases is comprised of the largest number of PTKs and include Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. The Src subfamily of enzymes has been linked to oncogenesis and immune responses.
Plk-1 is a serine/threonine kinase which is an important regulator of cell cycle progression. It plays critical roles in the assembly and the dynamic function of the mitotic spindle apparatus. Plk-1 and related kinases have also been shown to be closely involved in the activation and inactivation of other cell cycle regulators, such as cyclin-dependent kinases. High levels of Plk-1 expression are associated with cell proliferation activities. It is often found in malignant tumors of various origins. Inhibitors of Plk-1 are expected to block cancer cell proliferation by disrupting processes involving mitotic spindles and inappropriately activated cyclin-dependent kinases.
Cdc2 (cdk1)/cyclin B is another serine/threonine kinase enzyme which belongs to the cyclin-dependent kinase (cdks) family. These enzymes are involved in the critical transition between various phases of cell cycle progression. It is believed that uncontrolled cell proliferation, the hallmark of cancer, is dependent upon elevated cdk activities in these cells. The loss of control of cdk regulation is a frequent event in hyperproliferative diseases and cancer (Pines, Current Opinion in Cell Biology, 4:144-148 (1992); Lees, Current Opinion in Cell Biology, 7:773-780 (1995); Hunter and Pines, Cell, 79:573-582 (1994)). The inhibition of elevated cdk activities in cancer cells by cdc2/cyclin B kinase inhibitors could suppress proliferation and may restore the normal control of cell cycle progression.
Malignant cells are associated with the loss of control over one or more cell cycle elements. These elements range from cell surface receptors to the regulators of transcription and translation, including the insulin-like growth factors, insulin growth factor-I (IGF-1) and insulin growth factor-2 (IGF-2). [M. J. Ellis, “The Insulin-Like Growth Factor Network and Breast Cancer”, Breast Cancer, Molecular Genetics, Pathogenesis and Therapeutics, Humana Press 1999]. The insulin growth factor system consists of families of ligands, insulin growth factor binding proteins, and receptors.
A major physiological role of the IGF-1 system is the promotion of normal growth and regeneration, and overexpressed IGF-1R can initiate mitogenesis and promote ligand-dependent neoplastic transformation. Furthermore, IGF-1R plays an important role in the establishment and maintenance of the malignant phenotype.
IGF-1R exists as a heterodimer, with several disulfide bridges. The tyrosine kinase catalytic site and the ATP binding site are located on the cytoplasmic portion of the beta subunit. Unlike the epidermal growth factor (EGF) receptor, no mutant oncogenic forms of the IGF-1R have been identified. However, several oncogenes have been demonstrated to affect IGF-1 and IGF-1R expression. The correlation between a reduction of IGF-1R expression and resistance to transformation has been seen. Exposure of cells to the mRNA antisense to IGF-1R RNA prevents soft agar growth of several human tumor cell lines.
Apoptosis is a ubiquitous physiological process used to eliminate damaged or unwanted cells in multicellular organisms. Disregulation of apoptosis is believed to be involved in the pathogenesis of many human diseases. The failure of apoptotic cell death has been implicated in various cancers, as well as autoimmune disorders. Conversely, increased apoptosis is associated with a variety of diseases involving cell loss such as neurodegenerative disorders and AIDS. As such, regulators of apoptosis have become an important therapeutic target. It is now established that a major mode of tumor survival is escape from apoptosis. IGF-1R abrogates progression into apoptosis, both in vivo and in vitro. It has also been shown that a decrease in the level of IGF-1R below wild-type levels causes apoptosis of tumor cells in vivo. The ability of IGF-1R disruption to cause apoptosis appears to be diminished in normal, non-tumorigenic cells.
Inappropriately high protein kinase activity has been implicated in many diseases resulting from abnormal cellular function. This might arise either directly or indirectly, by failure of the proper control mechanisms for the kinase, related to mutation, over-expression or inappropriate activation of the enzyme; or by over- or underproduction of cytokines or growth factors also participating in the transduction of signals upstream or downstream of the kinase. In all of these instances, selective inhibition of the action of the kinase might be expected to have a beneficial effect.
The type 1 insulin-like growth factor receptor (IGF-1R) is a transmembrane RTK that binds primarily to IGF-1 but also to IGF-II and insulin with lower affinity. Binding of IGF-1 to its receptor results in receptor oligomerization, activation of tyrosine kinase, intermolecular receptor autophosphorylation and phosphorylation of cellular substrates (major substrates are IRS1 and Shc). The ligand-activated IGF-1R induces mitogenic activity in normal cells and plays an important role in abnormal growth.
Several clinical reports underline the important role of the IGF-1 pathway in human tumor development: 1) IGF-1R overexpression is frequently found in various tumors (breast, colon, lung, sarcoma.) and is often associated with an aggressive phenotype. 2) High circulating IGF1 concentrations are strongly correlated with prostate, lung and breast cancer risk. Furthermore, IGF-1R is required for establishment and maintenance of the transformed phenotype in vitro and in vivo (Baserga R. Exp. Cell. Res., 1999, 253, 1-6). The kinase activity of IGF-1R is essential for the transforming activity of several oncogenes: EGFR, PDGFR, SV40 T antigen, activated Ras, Raf, and v-Src. The expression of IGF-1R in normal fibroblasts induces neoplastic phenotypes, which can then form tumors in vivo. IGF-1R expression plays an important role in anchorage-independent growth. IGF-1R has also been shown to protect cells from chemotherapy-, radiation-, and cytokine-induced apoptosis. Conversely, inhibition of endogenous IGF-1R by dominant negative IGF-1R, triple helix formation or antisense expression vector has been shown to repress transforming activity in vitro and tumor growth in animal models.
Many of the tyrosine kinases, whether an RTK or non-receptor tyrosine kinase, have been found to be involved in cellular signaling pathways involved in numerous pathogenic conditions, including cancer, psoriasis, and other hyperproliferative disorders or hyper-immune responses. Therefore, much research is ongoing for inhibitors of kinases involved in mediating or maintaining disease states to treat such diseases. Examples of such kinase research include, for example: (1) inhibition of c-Src (Brickell, Critical Reviews in Oncogenesis, 3:401-406 (1992); Courtneidge, Seminars in Cancer Biology, 5:236-246 (1994), raf (Powis, Pharmacology & Therapeutics, 62:57-95 (1994)) and the cyclin-dependent kinases (CDKs) 1, 2 and 4 in cancer (Pines, Current Opinion in Cell Biology, 4:144-148 (1992); Lees, Current Opinion in Cell Biology, 7:773-780 (1995); Hunter and Pines, Cell, 79:573-582 (1994)), (2) inhibition of CDK2 or PDGF-R kinase in restenosis (Buchdunger et al., Proceedings of the National Academy of Science USA, 92:2258-2262 (1995)), (3) inhibition of CDK5 and GSK3 kinases in Alzheimers (Hosoi et al., Journal of Biochemistry (Tokyo), 117:741-749 (1995); Aplin et al., Journal of Neurochemistry, 67:699-707 (1996), (4) inhibition of c-Src kinase in osteoporosis (Tanaka et al., Nature, 383:528-531 (1996), (5) inhibition of GSK-3 kinase in type-2 diabetes (Borthwick et al., Biochemical & Biophysical Research Communications, 210:738-745 (1995), (6) inhibition of the p38 kinase in inflammation (Badger et al., The Journal of Pharmacology and Experimental Therapeutics, 279:1453-1461 (1996)), (7) inhibition of VEGF-R 1-3 and TIE-1 and 2 kinases in diseases which involve angiogenesis (Shawver et al., Drug Discovery Today, 2:50-63 (1997)), (8) inhibition of UL97 kinase in viral infections (He et al., Journal of Virology, 71:405-411 (1997)), (9) inhibition of CSF-1R kinase in bone and hematopoetic diseases (Myers et. al., Bioorganic & Medicinal Chemistry Letters, 7:421-424 (1997), and (10) inhibition of Lck kinase in autoimmune diseases and transplant rejection (Myers et. al., Bioorganic & Medicinal Chemistry Letters, 7:417-420 (1997)).
Inhibitors of certain kinases may be useful in the treatment of diseases when the kinase is not misregulated, but it nonetheless essential for maintenance of the disease state. In this case, inhibition of the kinase activity would act either as a cure or palliative for these diseases. For example, many viruses, such as human papilloma virus, disrupt the cell cycle and drive cells into the S-phase of the cell cycle (Vousden, FASEB Journal, 7:8720879 (1993)). Preventing cells from entering DNA synthesis after viral infection by inhibition of essential S-phase initiating activities such as CDK2, may disrupt the virus life cycle by preventing virus replication. This same principle may be used to protect normal cells of the body from toxicity of cycle-specific chemotherapeutic agents (Stone et al., Cancer Research, 56:3199-3202 (1996); Kohn et al., Journal of Cellular Biochemistry, 54:44-452 (1994). Inhibition of CDK 2 or 4 will prevent progression into the cycle in normal cells and limit the toxicity of cytotoxics which act in S-phase, G2 or mitosis.
Furthermore, CDK2/cyclin E activity has also been shown to regulate NF-kB. Inhibition of CDK2 activity stimulates NF-kB-dependent gene expression, an event mediated through interactions with the p300 co-activator (Perkins et al., Science, 275:523-527 (1997)). NF-kB regulates genes involved in inflammatory responses (such as hematopoetic growth factors, chemokines and leukocyte adhesion molecules) (Baeuerle and Henkel, Annual Review of Immunology, 12:141-179 (1994)) and maybe involved in the suppression of apoptotic signals within the cell (Beg and Baltimore, Science, 274:782-784 (1996); Wang et al., Science, 274:784-787 (1996); Van Antwerp et al., Science, 274:787-789 (1996). Thus, inhibition of CDK2 may suppress apoptosis induced by cytotoxic drugs via a mechanism which involves NF-kB and be useful where regulation of NF-kB plays a role in etiology of disease.
A further example of the usefulness of kinase inhibition is fungal infections: Aspergillosis is a common infection in immune-compromised patients (Armstrong, Clinical Infectious Diseases, 16: 1-7 (1993)). Inhibition of the Aspergillus kinases Cdc2/CDC28 or Nim A (Osmani et al., EMBO Journal, 10:2669-2679 (1991); Osmani et al., Cell, 67:283-291 (1991)) may cause arrest or death in the fungi, effectively treating these infections.
The identification of effective small compounds which specifically inhibit signal transduction and cellular proliferation by modulating the activity of receptor and non-receptor tyrosine and serine/threonine kinases to regulate and modulate abnormal or inappropriate cell proliferation, differentiation, or metabolism is therefore desirable. In particular, the identification of methods and compounds that specifically inhibit the function of a tyrosine kinase which is essential for angiogenic processes or the formation of vascular hyperpermeability leading to edema, ascites, effusions, exudates, and macromolecular extravasation and matrix deposition as well as associated disorders would be beneficial.
In view of the importance of PTKs to the control, regulation, and modulation of cell proliferation and the diseases and disorders associated with abnormal cell proliferation, many attempts have been made to identify receptor and non-receptor tyrosine kinase inhibitors using a variety of approaches, including the use of mutant ligands (U.S. Pat. No. 4,966,849), soluble receptors and antibodies (International Patent Publication No. WO 94/10202; Kendall & Thomas, 1994, Proc. Natl. Acad. Sci 90:10705-09; Kim et al., 1993, Nature 362:841-844), RNA ligands (Jellinek, et al., Biochemistry 33:1045056; Takano, et al., 1993, Mol. Bio. Cell 4:358A; Kinsella, et al. 1992, Exp. Cell Res. 199:56-62; Wright, et al., 1992, 1. Cellular Phys. 152:448-57) and tyrosine kinase inhibitors (International Patent Publication Nos. WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., 1994, Froc. Am. Assoc. Cancer Res. 35:2268).
More recently, attempts have been made to identify small molecules which act as tyrosine kinase inhibitors. Bis-, mono-cyclic, bicyclic or heterocyclic aryl compounds (International Patent Publication No. WO 92/20642) and vinylene-azaindole derivatives (International Patent Publication No. WO 94/14808) have been described generally as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), certain quinazoline derivatives (EP Application No. 0566266 A1; Expert Opin. Ther. Pat. (1998), 8(4): 475-478), selenoindoles and selenides (International Patent Publication No. WO 94/03427), tricyclic polyhydroxylic compounds (International Patent Publication No. WO 92/21660) and benzylphosphonic acid compounds (International Patent Publication No. WO 91/15495) have been described as compounds for use as tyrosine kinase inhibitors for use in the treatment of cancer. Anilinocinnolines (PCT WO97/34876) and quinazoline derivative compounds (International Patent Publication No. WO 97/22596; International Patent Publication No. WO97/42187) have been described as inhibitors of angiogenesis and vascular permeability. Bis(indolylmaleimide) compounds have been described as inhibiting particular PKC serine/threonine kinase isoforms whose signal transducing function is associated with altered vascular permeability in VEGF-related diseases (International Patent Publication Nos. WO 97/40830 and WO 97/40831).
IGF-1R performs important roles in cell division, development, and metabolism, and in its activated state, plays a role in oncogenesis and suppression of apoptosis. IGF-1R is known to be overexpressed in a number of cancer cell lines (IGF-1R overexpression is linked to acromegaly and to cancer of the prostate). By contrast, down-regulation of IGF-1R expression has been shown to result in the inhibition of tumorigenesis and an increased apoptosis of tumor cells.
International Patent Publication Nos. WO 03/018021 and WO 03/018022 describe pyrimidines for treating IGF-1R related disorders, International Patent Publication Nos. WO 02/102804 and WO 02/102805 describe cyclolignans and cyclolignans as IGF-1R inhibitors, International Patent Publication No. WO 02/092599 describes pyrrolopyrimidines for the treatment of a disease which responds to an inhibition of the IGF-1R tyrosine kinase, International Patent Publication No. WO 01/72751 describes pyrrolopyrimidines as tyrosine kinase inhibitors. International Patent Publication No. WO 00/71129 describes pyrrolotriazine inhibitors of kinases. International Patent Publication No. WO 97/28161 describes pyrrolo[2,3-d]pyrimidines and their use as tyrosine kinase inhibitors.
Parrizas, et al. describes tyrphostins with in vitro and in vivo IGF-1R inhibitory activity (Endocrinology, 138:1427-1433 (1997)), and International Patent Publication No. WO 00/35455 describes heteroaryl-aryl ureas as IGF-1R inhibitors. International Patent Publication No. WO 03/048133 describes pyrimidine derivatives as modulators of IGF-1R. International Patent Publication No. WO 03/024967 describes chemical compounds with inhibitory effects towards kinase proteins. International Patent Publication No. WO 03/068265 describes methods and compositions for treating hyperproliferative conditions. International Patent Publication No. WO 00/17203 describes pyrrolopyrimidines as protein kinase inhibitors. Japanese Patent Publication No. JP 07/133,280 describes a cephem compound, its production and antimicrobial composition. A. Albert et al., Journal of the Chemical Society, 11: 1540-1547 (1970) describes pteridine studies and pteridines unsubstituted in the 4-position, a synthesis from pyrazines via 3,4-dhydropteridines. A. Albert et al., Chem. Biol. Pteridines Proc. Int. Symp., 4th, 4: 1-5 (1969) describes a synthesis of pteridines (unsubstituted in the 4-position) from pyrazines, via 3-4-dihydropteridines.